I hammock in the Utah Rockies. Aspen grow pretty high up. In fact, I prefer a hammock, because I usually camp on a slope, with minimal flat spots (a common occurrence in "mountains", surprisingly). Like food said, I usually have to find some sort of flat spot for my non-hammock companions. The spots are never truly flat, just sort of flat. I think I converted (or at least stirred some interest) one of my companions to hammocks.